Unfortunately by attempting to explain away the obvious reading of he passages that you cited the main message throughout the bible is distorted. The bible fact is that God created only one man and one woman and that is how He defined marriage. Every verse in the bible talking about marriage only talks about marriage between a man and a woman. The message is inescapable.
Lets look at those two passages (Genesis 1:27 and Genesis 2:24) in light of Leviticus 18:22.
As I said in an earlier post in this thread, Leviticus does not use a paired set of words for the man and the woman; instead, it uses the word from one pair (zakar) for the man, and the word from another (ishshah) for the woman. Let's look at
these two verses and see what words they use:
So God created man (adam) in his [own] image, in the image of God created he him; male (zakar) and female (neqebah) created he them.
Genesis 1:27
Therefore shall a man (ish) leave his father and his mother, and shall cleave unto his wife (ishshah): and they shall be one flesh.
Genesis 2:24
Genesis 1:27 uses "adam" and then the pair "zakar" and "neqebah." Genesis 2:24 uses the pair "ish" and "ishshah."
"Adam" means man generically, often without regard to sex. The first part of the verse says that god created "adam" mankind. The second part mentions that mankind ("adam) comes in two varieties, man and woman, male and female. This is simply descriptive, and not proscriptive. Just as in verse 1:24, God created beasts: both cattle and "creeping things." Exact same construction. In this case it clearly just descriptive. Unless you want to say that the breeding of milk cows is wrong, since they should only be cross-bred with snakes.
"Ish" and "ishshah," husband and wife speaks of the marriage bond. The verse says that it is stronger even than the bond between child and parents. That is why when (in Matthew 19) Jesus quoted this verse --
in the context of a discussion on divorce -- He added "Wherefore they are no more twain, but one flesh. What therefore God hath joined together, let not man put asunder." There is nothing in this verse or in Jesus' use of it that forbids a marriage bond from forming between two men or two women, other than that it is not typical in most cultures.
The use of the split pair "zakar" and "ishshah" in Leviticus 18:22 and 20:13 suggests (but does not demand) the problem with "man-lying" is adultery: giving to another (a stranger or relative stranger) that which rightfully belongs to the spouse. If it relates at all to Jesus' teaching in Matthew 19, it is a sin because it betrays the marriage bond he has with his spouse. On the other hand, if the other man
is his spouse, there is no betrayal.